Rebels Concerned Over Syria's Chemical Weapons

Rebels now control more and more of Syria's territory, but a new problem has arisen, observers say: in its desperation, the regime of President Bashar al-Assad may decide to unleash its arsenal of chemical weapons. The rebels control several of the official border crossings, particularly those between Syria and Turkey, according to a report by NBC News correspondent Richard Engel, who has made repeated trips in and out of the country.